An acidic protein, Hf15, from Haliotis fulgens involved in biomineralization.

Biomineralization leads to the hardening of mineralized materials, such as the shell of Mollusk, to fulfill a wide range of functions, such as (but not limited to) skeletal support, protection of the soft tissues, navigation, etc. The study of the proteins responsible for this process, shell matrix proteins (SMPs), allows addressing questions related to structure-function relationship and to the mechanism of mineral formation, which is limited in gastropod species. In this study, a low molecular weight protein was isolated from the insoluble fraction after decalcification with acetic acid of the shell of Haliotis fulgens and, named Hf15. The unglycosylated protein has a theoretical molecular weight of 15 kDa, it possesses calcium and chiting binding properties. Hf15 can precipitate calcium carbonate in vitro in presence of different salts. Analysis by LC-MS of the five peptide sequences of Hf15 generated by trypsinization revealed that two peptides displayed homology to an uncharacterized protein 3-like from Haliotis rufescens, Haliotis asinia and H. sorenseni. The results obtained indicated that Hf15 is a novel SMP involved in shell mineralization in Haliotis fulgens.

Effect of Different Species of Prorocentrum Genus on the Japanese Oyster Crassostrea gigas Proteomic Profile.

This paper assesses the effects of exposure to toxic concentrations (1200 to 6000 cells/mL) of the dinoflagellates Prorocentrum lima, Prorocentrum minimum, and Prorocentrum rhathymum and several concentrations of aqueous and organic extracts obtained from the same species (0 to 20 parts per thousand) on the Crassostrea gigas (5-7 mm) proteomic profile. Through comparative proteomic map analyses, several protein spots were detected with different expression levels, of which eight were selected to be identified by liquid chromatography-mass spectrometry (LC-MS/MS) analyses. The proteomic response suggests that, after 72 h of exposure to whole cells, the biological functions of C. gigas affected proteins in the immune system, stress response, contractile systems and cytoskeletal activities. The exposure to organic and aqueous extracts mainly showed effects on protein expressions in muscle contraction and cytoskeleton morphology. These results enrich the knowledge on early bivalve developmental stages. Therefore, they may be considered a solid base for new bioassays and/or generation of specific analytical tools that allow for some of the main effects of algal proliferation phenomena on bivalve mollusk development to be monitored, characterized and elucidated.

Predictive performance of regression models to estimate Chlorophyll-a concentration based on Landsat imagery.

Chlorophyll-a (Chl-a) concentration is a key parameter to describe water quality in marine and freshwater environments. Nowadays, several products with Chl-a have derived from satellite imagery, but they are not available or reliable sometimes for coastal and/or small water bodies. Thus, in the last decade several methods have been described to estimate Chl-a with high-resolution (30 m) satellite imagery, such as Landsat, but a standardized method to estimate Chl-a from Landsat imagery has not been accepted yet. Therefore, this study evaluated the predictive performance of regression models (Simple Linear Regression [SLR], Multiple Linear Regression [MLR] and Generalized Additive Models [GAMs]) to estimate Chl-a based on Landsat imagery, using in situ Chl-a data collected (synchronized with the overpass of Landsat 8 satellite) and spectral reflectance in the visible light portion (bands 1-4) and near infrared (band 5). These bands were selected because of Chl-a absorbance/reflectance properties in these wavelengths. According to goodness of fit, GAM outperformed SLR and MLR. However, the model validation showed that MLR performed better in predicting log-transformed Chl-a. Thus, MLR, constructed by using four spectral bands (1, 2, 3, and 5), was considered the best method to predict Chl-a. The coefficients of this model suggested that log-transformed Chl-a concentration had a positive linear relationship with bands 1 (coastal/aerosol), 3 (green), and 5 (NIR). On the other hand, band 2 (blue) suggested a negative relationship, which implied high coherence with Chl-a absorbance/reflectance properties measured in the laboratory, indicating that Landsat 8 images could be applied effectively to estimate Chl-a concentrations in coastal environments.

Crassostrea gigas exposure to the dinoflagellate Prorocentrum lima: Histological and gene expression effects on the digestive gland.

Bivalve mollusks bioaccumulate toxins via ingestion of toxic dinoflagellates. In this study, Crassostrea gigas was used to investigate the effects related to Prorocentrum lima exposure. Oysters were fed with three diets Isochrysis galbana (2 × 10(6) cell mL(-1)) control treatment; algal mix of I. galbana (2 × 10(6)) and P. lima (3 × 10(3) cell mL(-1)); and P. lima alone (3 × 10(3) cell mL(-1)). Feeding behavior changes, histopathological alterations, and expression patterns changes of genes involved in cell cycle (p21, cafp55, p53), cytoskeleton (tub, act), and inflammatory process (casp1) were evaluated. Results indicated that the presence of diarrheic shellfish poisoning by P. lima cells decreased the clearance rate (p < 0.05), induced structural loss, significantly decreased tubule area of the digestive gland (p < 0.05), and up-regulated in expression all gene (p < 0.05), suggesting that toxic cells might trigger inflammatory tissue process, disturb cell cycle and cytoskeleton representing a risk to oysters integrity.

Effects of in vitro exposure to diarrheic toxin producer Prorocentrum lima on gene expressions related to cell cycle regulation and immune response in Crassostrea gigas.

BACKGROUND: Crassostrea gigas accumulates diarrheic shellfish toxins (DSP) associated to Prorocentrum lima of which Okadaic acid (OA) causes specific inhibitions of serine and threonine phosphatases 1 and 2A. Its toxic effects have been extensively reported in bivalve mollusks at cellular and physiological levels, but genomic approaches have been scarcely studied. METHODOLOGY/PRINCIPAL FINDINGS: Acute and sub-chronic exposure effects of P. lima were investigated on farmed juvenile C. gigas (3-5 mm). The Pacific oysters were fed with three dinoflagellate concentrations: 0.3, 3, and 30 ×10(3) cells mL-1 along with a nontoxic control diet of Isochrysis galbana. The effects of P. lima on C. gigas were followed by analyzing expression levels of a total of four genes, three involved in cell cycle regulation and one in immune response by polymerase chain reaction and real time quantitative PCR, where changes in time and cell concentration were found. The highest expression levels were found in oysters fed 3 × 10(3) cells mL-1 at 168 h for the cycle regulator p21 protein (9 fold), chromatin assembly factor 1 p55 subunit (8 fold), elongation factor 2 (2 fold), and lipopolysaccharide/ß-1, 3 glucan binding protein (13 fold above base line). Additionally, the transcript level of all the genes decreased in oysters fed wich the mixed diet 30 × 10(3) cells mL-1 of dinoflagellate after 72 h and was lowest in the chromatin assembly factor 1 p55 subunit (0.9 fold below baseline). CONCLUSIONS: On C. gigas the whole cell ingestion of P lima caused a clear mRNA modulation expression of the genes involved in cell cycle regulation and immune system. Over-expression could be related to DNA damage, disturbances in cell cycle continuity, probably a genotoxic effect, as well as an activation of its innate immune system as first line of defense.

Population characteristics of spotted rose snapper lutjanus guttatus caught as shrimp bycatch in the gulf of California / Características poblacionales del pargo lunarejo lutjanus guttatus capturado con la fauna de acompañamiento del camarón en el golfo de california / CARACTERÍSTICAS POPULACIONAIS DO "PARGO LUNAREJO" Lutjanus guttatus CAPTURADO COM A FAUNA DE ACOMPANHAMENTO DO CAMARÃO NO GOLFO DE CALIFÔRNIA

There are limited population biology studies of the spotted rose snapper Lutjanus guttatus. Adults of this highly valued commercial species are fished with gillnets and hook-and-line, while juveniles are caught as shrimp bycatch and usually discarded. The effects of this practice have not been studied. As a first step, this study assessed some population parameters of juvenile snapper caught by the Gulf of California shrimp fishery. We looked for early growth stages and determined by the least squares method the weight to standard length relationship as W= 0.000092, SL3.0509. Length frequency distributions were constructed; using the ELEFAN I method, von Bertalanffy growth parameters were found to be L¥= 515mm (standard length) and K= 0.13. Natural mortality (M= 0.35) was estimated from Pauly’s empirical and Ralston equations; and total mortality was calculated by the catch curve equation. The recruitment pattern extended throughout the year, with spring and summer peaks. The sex ratio was 1:1 and the length at capture was 80mm (standard length). With an apparently high fishing mortality levels, it is recommended that abundance and distribution studies be performed to determine the impact of shrimp fishing on this population.

Son escasos los estudios sobre la biología poblacional del pargo lunarejo Lutjanus guttatus. Los adultos de esta especie, de alto valor comercial, son capturados con redes agalleras y anzuelos mientras que los juveniles son capturados como fauna de acompañamiento de la pesca de camarón y usualmente descartados. Los efectos de esta práctica no han sido evaluados. Como un primer paso, en este estudio se estiman algunos parámetros poblacionales de juveniles del pargo lunarejo capturados en la pesquería de camarón del Golfo de California. Se indagaron estadios de desarrollo y se determinó mediante mínimos cuadrados la relación longitud estándar-peso como W= 0,000092; SL3,0509. Se construyeron distribuciones de frecuencia de talla, y usando el método ELEFAN I se encontraron los parámetros de crecimiento de von Bertalanffy L¥= 515mm (longitud estándar) y K= 0,3. La mortalidad natural (M= 0,35) fue estimada por la ecuación empírica de Pauly y la ecuación de Ralston, y la mortalidad total se calculó mediante la ecuación de la curva de captura. El patrón de reclutamiento se extendió a lo largo del año, con máximos en primavera y verano. La proporción sexual fue 1:1 y la talla media de captura fue 80mm (longitud estándar). Con una tasa de mortalidad pesquera aparentemente alta, se recomienda evaluaciones de la abundancia y distribución de la especie para determinar el impacto de la pesquería del camarón sobre esta población.

São escassos os estudos sobre a biologia populacional do "pargo lunarejo" Lutjanus guttatus. Os adultos desta espécie, de alto valor comercial, são capturados com redes de emalhar e anzóis enquanto que os juvenis são capturados como fauna de acompanhamento da pesca de camarão e usualmente descartados. Os efeitos desta prática não tem sido avaliados. Como um primeiro passo, neste estudo se estimam alguns parâmetros populacionais de juvenis do "pargo lunarejo" capturados na pescaria de camarão do Golfo da Califôrnia. Indagaram-se estágios de desenvolvimento e se determinou mediante mínimos quadrados a relação longitude estandar-peso como W= 0,000092; SL3,0509. Construiram-se distribuições de frequência de tamanho, e usando o método ELEFAN I se encontraram os parâmetros de crescimento de von Bertalanffy L¥= 515mm (longitude estandar) e K= 0,3. A mortalidade natural (M= 0,35) foi estimada pela equação empírica de Pauly e a equação de Ralston, e a mortalidade total se calculou mediante a equação da curva de captura. O padrão de recrutamento se extendeu ao longo do ano, com máximos em primavera e verão. A proporção sexual foi 1:1 e o tamanho médio de captura foi 80mm (longitude estandar). Com uma taxa de mortalidade pesqueira aparentemente alta, se recomenda avaliações da abundância e distribuição da espécie para determinar o impacto da pescaria do camarão sobre esta população.

Respuesta antioxidante enzimática en frutos de Chile ancho (Capsicum annuum L) bajo condiciones de estrés salino / Antioxidant enzymatic response of hot pepper (Capsicum annuum L) under saline stress conditions

Se estudió la respuesta de la superóxido dismutasa (SOD) y la catalasa (CAT) en frutos de chile (Capsicum spp. cv. Caballero) al cometer las plantas a estrés salino moderado. Las plantas fueron expuestas en macetas durante 90 días a cinco tratamientos: control (agua potable; 1,3dS·m¯¹) y agua de mar (2,8 y 4,0dS·m¯¹). Los frutos fueron cosechados en etapa de maduración y se midió pigmentación a la madurez, número, largo, ancho, peso fresco, contenido mineral (Ca, Mg, K, Mn, Na y Cl), proteínas, actividad de SOD y CAT, lipoperoxidación y ácido ascórbico. No hubo diferencias significativas en número de frutos, largo, ancho y peso fresco. Los tratamientos produjeron diferencias en pigmentación de los frutos en la madurez, cambiando al rojo en ambas fuentes salinas a 4,0dS·m¯¹. Las proteínas solubles aumentaron en 2,8dS·m¯¹, pero disminuyeron al aumentar la CE en ambas fuentes salinas. Los contenidos de Ca²+, Mg²+, K+, Mn²+ disminuyeron al incrementar la CE, mientras Na+ y Cl¯ aumentaron en 4,0dS·m¯¹ (NaCl). El ácido ascórbico aumentó ligeramente en 2,8dS·m¯¹. El estrés salino incrementó la lipoperoxidación y la actividad de SOD y CAT siendo mayores en 4,0dS·m¯¹, y la respuesta en 2,8dS·m¯¹ en ambas fuentes de salinidad pareció mantener la homeostasis celular sin alterar la maduración. Se sugiere la posibilidad de utilizar las enzimas SOD y CAT como biomarcadores de maduración en frutos de chile bajo estrés salino, al mostrar una alta actividad en la maduración cuando se utilizó NaCl o agua de mar.